Revert "System scoping in bundles"

This reverts commit a47503c.

lib/compile.js

@@ -176,22 +176,18 @@ function compileTree(loader, tree, compileOpts, outputOpts, cache) {
   })
   .then(function() {
 
+    // if any module in the bundle is AMD, add a "bundle" meta to the bundle
+    // this can be deprecated if https://github.com/systemjs/builder/issues/264 lands
+    if (modules.some(function(name) {
+          return tree[name].metadata.format == 'amd';
+        }))
+      outputs.unshift('"bundle";');
+
     // static bundle wraps with a self-executing loader
     if (compileOpts.static)
       return wrapSFXOutputs(loader, tree, outputs, entryPoints, compileOpts);
     else
-      return Promise.resolve(addPackageConfig(loader, tree, outputs, entryPoints, compileOpts))
-      // normal bundle wrap in System closure in case we have a different global
-      .then(function(outputs) {
-        outputs.unshift('(function(System) {');
-        outputs.push('})(System);');
-
-        // bundle informs:
-        // - builder to know this can be used in subtractions
-        // - loader to know to apply regex to check for transpiler runtimes
-        outputs.unshift('"bundle";');
-        return outputs;
-      });
+      return addPackageConfig(loader, tree, outputs, entryPoints, compileOpts);
   })
   .then(function(outputs) {
     // NB also include all aliases of all entryPoints along with entryPoints